1. Field of the Invention
The present invention relates to polypeptides having succinyl-CoA:acetoacetate transferase activity and polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides.
2. Description of the Related Art
Concerns related to future supply of oil have prompted research in the area of renewable energy and renewable sources of other raw materials. Biofuels, such as ethanol and bioplastics (e.g., particularly polylactic acid) are examples of products that can be made directly from agricultural sources using microorganisms. Additional desired products may then be derived using non-enzymatic chemical conversions, e.g., dehydration of ethanol to ethylene.
Polymerization of ethylene provides polyethylene, a type of plastic with a wide range of useful applications. Ethylene is traditionally produced by refined non-renewable fossil fuels, but dehydration of biologically-derived ethanol to ethylene offers an alternative route to ethylene from renewable carbon sources, i.e., ethanol from fermentation of fermentable sugars. This process has been utilized for the production of “Green Polyethylene” that—save for minute differences in the carbon isotope distribution—is identical to polyethylene produced from oil.
Similarly, isopropanol and n-propanol can be dehydrated to propylene, which in turn can be polymerized to polypropylene. As with polyethylene, using biologically-derived starting material (i.e., isopropanol or n-propanol) would result in “Green Polypropylene.” However, unlike polyethylene, the production of the polyethylene starting material from renewable sources has proved challenging. Proposed efforts at propanol production have been reported in WO 2009/049274, WO 2009/103026, WO 2008/131286, and WO 2010/071697. However, no efficient fermentation process for propanol has been reported. It is clear that the successful development of a process for the biological production of propanol requires careful selection of enzymes in the metabolic pathways as well as an efficient overall metabolic engineering strategy.
It would be advantageous in the art to provide polypeptides having succinyl-CoA:acetoacetate transferase activity which may aid in improving acetoacetate and/or isopropanol production. The present invention provides polypeptides having succinyl-CoA:acetoacetate transferase activity and polynucleotides encoding the polypeptides.